For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningEngine Oil Life System
When to Change Engine Oil
This vehicle has a computer system that indicates when to change the engine oil and filter. This is based on a combination of factors which include engine revolutions, engine temperature, and miles driven.
Based on driving conditions, the mileage at which an oil ...
Environmental Fallout (Acid Rain)
Caution: Refer to Clearcoat/Ultraviolet Screeners Caution in the
Preface section.
Note: Always refer to the manufacturer's packaged instructions for
the detailed procedures of materials used for compounding and/or
polishing.
Since the severity of the condition varies from area to area, proper ...
Rear Compartment Lid Adjustment
Rear Compartment Lid
Caution: Refer to Fastener Caution in the Preface section.
Procedure
Loosen the rear compartment lid hinge bolt (Qty: 4) to
adjust the rear compartment lid.
Adjust the rear compartment lid in order to obtain an even gap between
the rear compartment ...